1. Field of Invention
The present invention relates to a method for checking and/or monitoring the correct operation of an adding device of a medical apparatus, the medical apparatus including an extracorporeal circuit with which the adding device is connected such that an agent can be introduced into the extracorporeal circuit by means of the adding device.
2. Description of the Prior Art
In particular, the medical apparatus can be a dialysis machine, in which—as also in other extracorporeal methods—an anticoagulant such as heparin or citrate must be added to the blood. For this purpose, the medical apparatus includes an adding device, usually in the form of a syringe pump, which contains the agent to be added. Before commencement of the treatment, the adding device is connected with the extracorporeal circuit, i.e. with an extracorporeal set of tubes.
In the case of syringe pumps, a syringe with the agent initially is inserted in the syringe pump and connected with the extracorporeal circuit. For adding the agent from the syringe into the extracorporeal circuit, a tappet is provided, which presses the syringe plunger into the syringe. For this purpose, the tappet is moved correspondingly via a spindle and a spindle drive. Monitoring the dose administered by such adding device is effected e.g. during the dialysis treatment by measuring the tappet displacement, e.g. by scanning by means of a resistance path. The distance covered by the delivery tappet and hence the quantity added thus can be calculated.
In this way, however, the correct addition merely is checked on the side of the syringe pump, whereas it is not ensured whether the quantity of anticoagulant to be infused actually arrives in the extracorporeal circuit. In known machines, it is also checked initially at the beginning of the treatment whether the syringe pump is correctly connected. During the time of the treatment, however, a disconnection or other malfunction could not be detected automatically.
In particular in the case of an incorrectly inserted infusion syringe, an initial coupling test could be terminated successfully. Problems resulting from the incorrectly inserted infusion syringe, which only arise during the treatment and lead to a deviation of the prescribed infusion dose, might, however, not be detected as the administered infusion dose merely is monitored indirectly via the tappet movement, but not directly via the plunger movement.